<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>

<script>
  function Person(name, age) {
    this.name = name;
    this.age = age;
  }
  var person = new Person('xiaoming', 12);
  console.log(person);
  var a = person.constructor;
  var a2 = person.__proto__.constructor;
  var b = Person.prototype.constructor;
  var c = Person.constructor;
  var d = Function.constructor;

  console.log(a === b && a === a2); // true
  console.log(b === c); // false
  console.log(c === d); // true
  console.log(Function.constructor === Function); // true

  console.log(person.__proto__); // Object
  console.log(person.__proto__.__proto__); // Object.prototype
  console.log(person.__proto__.__proto__.__proto__); // null

  console.log(person instanceof Person);
  console.log(person.__proto__ instanceof Person);
</script>

</body>
</html>
